1. Field of the Invention
The present invention relates to a document feeding apparatus and a reproducing machine having the document feeding apparatus which can select a circulating copy mode wherein a document which is fed from a document supply portion and exposed on a platen glass plate is returned to the document supply portion or a non-circulating copy mode wherein the exposed document is discharged to a discharge paper tray provided outside the machine.
2. Description of the Prior Art
Generally speaking, some document feeding apparatus (ADF) of this kind can separate and feed the documents stacked on a document stacker one by one onto the platen glass plate of a reproducing machine and to discharge the documents exposed on the platen glass plate to a discharge dish outside of the machine Another document feeding apparatus (RDF) can perform repeated feeding by returning the exposed documents to the document stacker. Since these document feeding apparatus are equipped at their paper feed aperture with a document separating mechanism, they cannot feed either documents which are so liable to be broken that cannot withstand passage through the separating mechanism or documents which are difficult to be separated by the separating mechanism, such as stacked or folded documents. If such documents are circulated automatically, the reliability is reduced remarkably. In order to feed such documents, therefore, those document feeding apparatus are provided additionally to a paper feeding aperture 141 of a document stacker 140 of ADF or RDF, as shown in FIG. 14. For example, a manual insertion plate 145 is provided to communicate with entrance portions of a platen glass plate 142 of the reproducing machine and a feeding belt 143 arranged above the platen glass plate 142, so that a document can be fed on the platen glass in the manual insertion system (SDF) without passing through the separating means for the paper feeding aperture of ADF or RDF. Reference numeral 146 denotes a paper discharge plate.
Despite of this fact, however, the system has operation problems and a complicated construction because of two paper feed apertures.
Further, the copy surface of the document fed by ADF or RDF mode becomes opposite to that fed by the manual insertion mode, so that it is necessary to turn the document upside down according to the selected mode.
In such reproducing machine having the document feeding apparatus, the document fed on the platen glass plate is stopped at the exposing position and exposed while the optical exposure system is moved, irrespective of the circulating copy mode and the non-circulating copy mode.
In the circulating copy mode, the document automatically fed from the document stacker is exposed at the exposure processing portion and then returned to said document stacker, so that each page of the document is copied to obtain one copy without failure in order (RDF). On the contrary, in the non-circulating copy mode, the document automatically fed from the document stacker or fed manually is exposed at the exposure processing portion to obtain copies of required number and then discharged to the paper discharging tray mounted outside the machine (ADF or RDF).
Accordingly, it is necessary to stop the document on the exposure processing portion (platen glass plate) and to move the optical exposure system when the copying is carried out by the non-circulating copy mode. If, however, the document is stopped on the platen glass plate and the optical exposure system is moved every copy time in the circulating copy mode, a much time is required.